When you use Pick Points to define your boundaries, AutoCAD analyzes all objects in the boundary set to derive the boundary definition. The boundary set is the set of objects that AutoCAD treats as eligible for analysis when defining boundaries from a specified point.
By default, the boundary set consists of all objects fully or partially [...]
You can define a hatch boundary by specifying points directly. For example, you may want to illustrate a pattern fill in a small section of a drawing, as shown in the following illustration.
When you use Pick Points to define your boundaries, you can remove any detected islands from your boundary definition. In the following procedure, you remove islands so that the part is hatched as illustrated.
Island detection methods specify whether to include objects within the outermost boundary as boundary objects when you are using Pick Points. These internal objects are known as islands. By default, AutoCAD uses the Flood island detection method. The Flood method includes islands as boundary objects, as shown in the following illustration. How AutoCAD hatches the [...]
Hatched areas created with BHATCH are associative by default. You can remove hatch associativity at any time or you can change the default to create a nonassociative hatch. If you specify points to create an associative hatch, specify only one internal point per hatch block placement. Specifying more than one internal point can produce unexpected [...]